Mechanisms Involved in Hekobacter Inflammation pylori-Induced

Back&ound: Helicobacter pylori infection is associated with mucosai inflammation. The aims of the present study were to assess whether a water extract of H. pylori promotes neutrophil (polymorphonuclear leukocyte [PMN]) adherence to endotheliai cells and define the molecular basis of this adhesive interaction. Methods: lntravitai microscopy was used to study leukocyte adhesive interactions in rat mesenteric venules in situ. PMN-endothelial ceil adhesive interactions were studied in vitro using human PMNs and monolayers of human umbilical vein endotheiiai ceils (HUVEC). Results: In vivo, superfusion of rat mesentery with the H. pyloriextract increased leukocyte adhesion and emigration in venules. In vitro, adhesion of human PMNs to HUVEC was increased by the H. pylori extract in a concentration-dependent manner. Pretreatment of HUVEC atone with H. py/ori extract had no effect on PMN adherence, whereas pretreatment of PMN alone significantly increased their adherence to HUVEC. The extract-induced adhesion was significantly diminished by monoclonal antibodies (MAb) directed against either CD1 la, CD1 1 b, or CD18 on neutrophiis, and by MAbs against intercellular adhesion molecule-l (ICAM-l), but not Eor P-selectin, on endotheliai cells. Conclusions: These studies suggest that products of H. pylori elicit gastrointestinal infiammation by promoting PMN adhesion to endothelial ceils via CDlla/CD18- and CDllb/ CD 18-dependent interactions with ICAM- 1.